TechSpot

Computer doesnt start. Green light on motherboard

By micky_577
Sep 13, 2008
  1. Hi,

    My Problem:

    Tonight I went to turn on my PC and the machine was "dead" so to speak. No fans/drives attempting to boot up or anything, even momentarily, just a completely dead machine. In addition to the machine being "dead", I noticed that there is a green light on the motherboard that remains on when the machine is plugged in with the PSU turned on. PSU fan is not turning on either.

    Things that I have done to try to fix this:
    -Change the power supply.
    -Bypass power button switch.
    -Reset bios by removing battery. Also tried different battery.
    -Remove RAM, hard disk and CD drive. No beep.

    Obviously, none if this has brought my PC back to life so I am wondering what could be causing this? The PC was not moved or anything recently and no hardware / software changes of any sort have been done recently.

    However!....(I dont know if this is worth mentioning or not) it might be helpful to make the following known: When PSU is connected, there is green light on motherboard.

    Also, when I lift 20 pin power connection to motherboard( littel bit not compeletely), PSU fan, processor fan runs and get orange light on cabinet. Also green light on motherboard turn blinking green light. But still computer is not booting up and nothing on monitor.

    What do you think could be the cause of this? Any ideas?


    System Specs:

    Emachine T2898
    Operating System: Windows XP
    RAM: 2x 512mb (1gb Total)
     
  2. nickc

    nickc TechSpot Paladin Posts: 1,650

    PSU, and hope fully u have not blown the mother board too.
     
  3. micky_577

    micky_577 TS Rookie Topic Starter

    If it was PSU, it would have not run CPU fan and PSU fan upon lifting power connection
     
  4. fw2004

    fw2004 TS Enthusiast Posts: 203

    Was there a lightning storm recently?
    Does anyone in the house use any heavy motorized equipment (table saw, grinder, etc)?
    Were there any power outages, fluctuations, brownouts, or noticeable surges recently?
    Do you have the system connected to a good surge suppressor?

    You may have been hit with a surge or high-voltage spike.

    A few suggestions, if you haven't already done:

    1) Unplug all external devices, including monitor, keyboard, and mouse. One of these devices may have a short, and cause the system to fail.
    After everything is unplugged, try to turn on the system. It should at least give you some beeps, and the fan should come on, even without a keyboard, mouse, or monitor connected.

    2) Unplug all hard drives, floppy, and CD drives.
    Try powering up with these devices disconnected. Again, there should at least be some beeps, and fans should run.

    3) Check all plug-in cards to make sure they are properly seated.
    Note: When working inside the computer, you should connect a ground wire to the case, and wear a grounded wrist strap to prevent damage due to static discharge.
    My method of doing this is to leave the computer plugged into the power strip, then turn off either the switch in back of the PSU (if there is one), or if there is not, turn off the power strip to which the computer is connected. You want to have the ground wire connected (through the 3-wire cord) but not have any power on the motherboard.

    Note: Turning off the computer without switching off the PSU or the power strip does not remove power from the MOBO. There is always some power when the PSU is powered up, even when the computer is not running, thus your green LED being lit. Never remove or install internal components when there is power on the MOBO.

    If you don't have a wrist strap, touch the computer case periodically to make sure you are not carrying a charge.

    If you remove any cards, store them in special anti-static bags (the ones the cards came in) to prevent damage from static.

    4) Check that the CPU is properly seated: Caution- Be very careful when doing this. Follow MFR instructions when removing/installing the CPU and heat sink.
    Again, make sure that the machine, and you are grounded, and that no power is applied to the system.

    5) Never remove power from the MOBO while the PSU is powered up. You said you pulled the 20-pin plug part-way out, and saw some life in the system.
    This alone can blow things up. The MOBO is designed to run with all the PSU voltages at correct level. Having just one of them lower, or missing can cause system failure and damage!

    If all of the above fail, I recommend a completely new system. I would be hesitant to try replacing the MOBO alone, considering the possibility that one or more of the cards (video, etc), or the CPU are bad, and may blow out a bran-new MOBO.
    On the other hand, a bad MOBO could blow out a new CPU.

    Good luck.

    FW
     
  5. micky_577

    micky_577 TS Rookie Topic Starter

    I tried to boot without hard drives, floppy, and CD drives but no effect. I also have tried another PSU. I think its MBO or CPU but dont understand why all fan runs when I pulled the 20-pin plug part-way out. Please advice.
     
  6. Tedster

    Tedster Techspot old timer..... Posts: 10,074   +13

    read the "NO POST" guide in the guides forum.
     
  7. egydarceyes

    egydarceyes TS Rookie

    Hey Micky.. I have the same exact issue with my T2958 emachines computer.
    I have tried most things you've posted, the only last thing that makes sense is that the board has blown.

    Have you figured out a solution at all?

    Thank you
     
  8. nickc

    nickc TechSpot Paladin Posts: 1,650

    if the mother board is blown the only fix is to get a new mobo.
     
  9. egydarceyes

    egydarceyes TS Rookie

    That's the thing.. I don't know for sure. It could just be the PSU.
    I think I already asked a tech online and he gave me the $50 price for a brand new one.
    I'm not sure if it's proprietary or not to see if I can get a cheaper one somewhere else.
     
  10. nickc

    nickc TechSpot Paladin Posts: 1,650

    a $50. psu is cheap. the psu is the heart of the computer and should be cut short. if it is not working right the whole computer will not work right.
     
  11. Tedster

    Tedster Techspot old timer..... Posts: 10,074   +13

    The only way to test a PSU is with a test Tool and a multimeter. Just because it powers on does not mean the PSU is ok.
     
     
  12. bigmacnfrys

    bigmacnfrys TS Rookie

    I'm having the same issue. I bought a new case and power supply put iy all together nothing. I have a green light on mb but will not power on No fans even for a second.
     
  13. bigmacnfrys

    bigmacnfrys TS Rookie

    I got my fixed kinda new mother board ,cpu, and new ram.
     
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